1. Field of Invention
This invention relates to newspaper inserters compatible with high-speed newspaper presses and more particularly to newspaper inserters of the type utilizing a vacuum type insert feeder to supply inserts to pockets mounted on an assembly conveyor previously supplied with newspaper jackets.
2. Brief Description of the Prior Art
The newspaper inserter of the present invention is of the general type disclosed in the patents to Merker et al, U.S. Pat. No. 3,926,423; Merker et al, U.S. Pat. No. 3,988,016; and Merker et al, U.S. Pat. No. 4,046,367.
U.S. Pat. No. 3,988,016 describes an insert feeder adapted to propel inserts into an assembly conveyor carrying V-shaped cross sectional pockets. The pockets receive newspaper jackets in-line, that is directly from a press, and mechanically spread the jackets for receipt of an insert from an insert feeder located at a position vertically above the assembly conveyor. The insert feeder mechanism utilizes a vacuum applied to the bottom insert, of several inserts stacked in a hopper, through a plurality of sucker arms to pull the bottom insert in the stack down to a position where it is nipped by a pair of small driven rollers. The sucker arms pivot below and behind the line of feed and must wait to return to its pick-up position until such time as the insert has cleared the rollers. In this configuration only 25% of the cycle time is actually spent driving an insert in the insert feeder. This limitation in turn dictates that the nipping rollers rotate at a very high speed of over 6000 r.p.m. to achieve an insert feeding output sufficient to match press speeds, approximately 40,000 issues per hour. To achieve these very high rotational speeds, the inserter must be built to very high specifications, resulting in a high cost.
Inherent problems arise from the use of high rotational speeds, which make compound operational problems which result in the use of any newspaper inserter. Two driven rollers leaves a very narrow choice to the user of the insert feeder as to just what thickness of insert can be handled because both rollers must be either set in fixed position, without provision for variation, or a complex mechanism used to allow variable spacing between the driven rollers. Two driven rollers also complicates gearing, lubrication and space requirements for the insert feeder.
Other prior art devices also use sucker arms in a similar manner, for example as shown in U.S. Pat. No. 3,966,186 issued June 29, 1976 to Helm. However, as in the art already discussed, the sucker arm must wait to return to its pick-up position until after the insert is driven through the nipping rollers. This results in an inefficient use of cycle time in an application where speed is the critical requirement.
The U.S. Pat. No. 4,046,367 patent discloses a newspaper inserter for feeding jackets in-line from a high-speed press to an assembly conveyor bearing V-shaped cross sectional pockets which receive the jackets from the press. The jackets are mechanically spread and held open to receive an insert from an insert feeder of the type disclosed in U.S. Pat. No. 3,988,016 discussed above. The insert feeder is disposed above the assembly conveyor transporting the pockets. The pockets consist of a fixed side and a pivotable side and are spaced apart at the bottom, while a belt conveyor is synchronized to travel underneath the pocket and support the assembled product. The product, jacket and enclosed insert, is automatically discharged, when the belt conveyor ends at a preselected position, onto a discharge conveyor. The discharge conveyor conveys the product underneath the superimposed assembly conveyor, to a horizontal discharge conveyor, which moves the product at a right angle away from the assembly conveyor to a remote locale for further handling. No specific provision is made for sensing success or failure of any of the steps of the method disclosed. Specifically, no provision is made for sensing any misaligned jackets coming from the press, missed delivery of jackets to the pockets, or missed delivery of an insert.
Misalignment of a jacket as it is conveyed from the press to the pockets along the assembly conveyor can cause a jam if the jacket, as ultimately fed, misses the pocket to which it is assigned by an indexing conveyor. The failure to feed a jacket to a specific pocket is not as critical. However, in efficiently using the insert feeder, it is desirable to not waste an insert on an empty pocket. The failure to feed an insert, also is not operationally critical, but results in a defective product which can be readily made acceptable if it is specially handled and separated from the others.
The art cited above does disclose direct or in-line feeding of a newspaper jacket from a press to a newspaper inserter machine. No specific teaching of these patents discloses the mechanism by which a lapped stream of newspaper jackets from a high-speed press can be unlapped and indexed for proper timed feeding to the V-shaped cross sectional pockets mounted on the assembly conveyor. Off-line feeding and stacking jackets from the press for later assembly, is not shown for the newspaper inserter of U.S. Pat. No. 4,046,367. Other methods use exclusively off-line assembly, but make no provision for in-line assembly.
Forming a single lapped stream from two different newspaper streams, utilizing indexing pins along a belt conveyor is shown in U.S. Pat. No. 3,874,649 issued Apr. 1, 1975 to Bryson et al. Application of that system to a lapped stream coming from a press for ultimate timed feeding to the assembly conveyor of the present invention is not known. Neither adequate means for sensing jacket location for proper alignment while being indexed, nor means for diverting any misaligned jackets are shown in such an arrangement. Failure to protect the machine from a misaligned jacket can be critical in terms of the potential for a jam, if the jacket is delivered out of synchronization with the assembly conveyor.
The V-shaped pockets of the prior art have found wide acceptance in various newspaper inserter and newspaper handling devices. Gravity discharge, of the jacket and enclosed newspaper insert, has been slowed by frictional forces when utilizing the pocket configuration and articulation as previously known. The quickest possible discharge of the product to the discharge conveyor is essential in achieving high operational speeds, as well as in avoiding serious jams and lost time in trouble-shooting that should be spent in production.
Part of the problem associated with pocket configurations of the prior art arises from the fact that inserts are fed to the pockets in a direction opposite that of the line of travel of the assembly conveyor. Because of the combination of the high speeds of the assembly conveyor and the oppositely moving insert, pocket configurations of the past have had to reduce the impact forces where possible in order to minimize the chance of a misaligned insert feed. This has been done by slanting the pocket side which is impacted by the insert, with corresponding increased frictional forces to contend with on discharge.
Another difficulty presented by the prior art is that mechanically spreading the newspaper jackets depends upon an off-fold (the extent that one half of the jacket extends beyond the other half) of the jacket being within a specified range. The off-fold, or extended half, is clamped by appropriate gripping hook mechanisms located on the uppermost portion of the pocket, and the jacket is mechanically spread for receipt of an insert. This mechanical gripping, coupled with the fact that press cut-offs can vary up to three inches, requires that the height of the gripping hooks above the assembly conveyor must be altered for each pocket when a new dimension of cut-offs is used. Manual adjustment of the distance between the synchronous belt supporting the bottom of the newspaper jacket and the gripping hook mechanism is time consuming when it is realized that all pockets must be individually adjusted.
The particular characteristics of the insert feeder of the present invention make it desirable for small stacks of inserts to be fed to a hopper of the insert feeder so that the forces transmitted to the bottom insert of the stack held in the hopper are minimized. This is best accomplished by automatically and sequentially feeding lightweight stacks of inserts to the hopper. A further advantage of conveying pre-stacked inserts to the insert feeder is the automation of the entire newspaper inserter system to the maximum extent possible. An example of an apparatus for advancing bundles to a hopper of a newspaper handling machine and then stripping the bundles from the conveyor and dropping them from a relatively high position into a hopper is shown in U.S. Pat. No. 4,046,370 issued Sept. 6, 1977 to Navi. The dropping of relatively heavy bundles of inserts from high positions above the hopper transmits excessive forces. These forces transmitted through the insert stack can cause the separation of several inserts for pick-up by the sucker arms, rather than single inserts necessary for the system to operate.